Waterproof joint?

[Jack07]

Hi,
I am using moisture board in my shower with waterproofing kit before tiling. What is best to use to fill the joints in the plasterboard?

I was told to use glass fibre mesh and a quality tile adhesive?

Any advice?

Thanks

 

[PrenticeBoyofDerry]

If your tanking the walls, use polyester matting or tape. Depending which kit you are using, the tapes can be applied by the use of first coat of waterproof coating. But read the manufactures instruction with kit for guidance.

 

[Karis]

By “moisture board” do you mean moisture resistant plaster board? Plasterboard of any sort is not ideal in wet areas even when tanked. If you have a recessed shower valve or concealed pipes, the back of the boards are always going to be vulnerable to water damage in the event of a leak. A waterproof tile backer board is by far superior; it doesn’t require tanking & the cost will be about the same as PB when if you include the cost of tanking.

What “waterproofing kit” are you using? They usually come with a self adhesive waterproof polyester tape which will bridge gaps up to 1.5mm when used with the tanking compound. You could use a waterproof tub mix tile adhesive but do not use cement powder based adhesive unless you acrylic prime the PB or you risk a reaction between the cement & gypsum in the PB. Do not use silicone.

You will probably need to use a bonding primer before applying the tanking anyway. What type/weight/size tiles are you laying?